TY - CONF A1 - Auersch, Lutz A1 - Said, Samir A1 - Rohrmann, R. T1 - Measurement and evaluation tools for ground and building vibrations from industrial pro-cesses, construction work, traffic and other sources N2 - Vibration measurements have many causes and many technical and natural sources. Problems can sometimes be solved by short-term measurements, but in many cases, a long-term measurement is necessary. In long-term measurements of days, weeks, months and even years, it is easy to collect a huge quantity of raw data, but at the end, the post-processing of these data can be exhausting (for example one-year vibration data of a wind energy tower). A software has been developed which con-sists of measuring and evaluation routines where the measuring routines can operate different meas-uring systems and different measuring cards. The main advantage of this software is the fact that the interesting evaluations can be integrated in the measuring process so that the characteristics of the vibration can be extracted without storing all the raw data. Only important time segments are stored, for example train passages. The overall concept of the software and the main evaluation routines will be described in some details. Examples of our measurement experience will illustrate the capabilities of the software. 1) Surveying construction work in nearby sensitive buildings (for example an old wind tunnel), including a stable alarm system and meaningful vibration limits. 2) Prediction of train-induced vibration for a planned building to prevent annoyance and to improve the building design. 3) Modal analysis and long term measurements of several single- or multi-span, concrete or steel bridges 4) Modal and wave analysis of coupled floors in a historical building (“Neues Palais” at Potsdam). 5) Soil properties of various measurement sites (different routines to evaluate the dispersion). Moreover, from many projects, amplitudes, frequencies, and attenuation laws have been collected and analysed for the different sources such as vibratory or impact pile driving and ground compaction, demolition work with different machines, blasting in quarries and in tunnel works, bomb and mine clearing. T2 - 28th International Congress on Sound and Vibration CY - Online meeting DA - 24.07.2022 KW - Ground vibration KW - Building vibration KW - Measurement KW - Evaluation KW - Modes KW - Waves PY - 2022 SP - 1 EP - 8 AN - OPUS4-56602 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Müller, R. A1 - Brechbühl, Y. A1 - Lutzenberger, S. A1 - Said, Samir A1 - Auersch, Lutz A1 - Guigou-Carter, C. A1 - Villot, M. A1 - Müller, R. ED - Degrande, G. ED - al., et T1 - Vibration Excitation at Turnouts, Mechanism, Measurements and Mitigation Measures N2 - There is a strong need for cost-effective mitigation measures for turnouts. SBB has initiated a series of examinations using different methodologies to gain a deeper understanding of the excitation mechanisms at low frequencies, in addition to that obtained in the RIVAS project. To date it is not yet clear what constitutes a complete measurement data set that would enable understanding most of the vibration excitation mechanisms in turnouts. Increasing vibration at turnouts in comparison to normal track is observed for all measured frequencies. The different methodologies are presented in the paper. Under-sleeper pads (USP) are a cost-effective method to reduce vibration at frequencies above 63 Hz (1/3 octave), but there is probably no improvement for frequencies below 63 Hz. A first test of new frog geometry did not show relevant improvements in Vibration emission in comparison to a reference frog geometry. Axle box acceleration measurements are an interesting method to identify defects in a turnout. A specialized measurement system of rail roughness could identify certain geometry Problem areas for some frogs. Noise increases also are observed at turnouts for frequencies ranging between 80 to 1000 Hz. The use of railway source models to calculate contact forces for ballasted track and turnouts seems promising, in particular for understanding the influence of ground. KW - Turnout KW - Switch KW - Vibration excitation KW - Vibration measurements PY - 2021 SN - 978-3-030-70288-5 DO - https://doi.org/10.1007/978-3-030-70289-2_42 SN - 1612-2909 VL - 150 SP - 403 EP - 410 PB - Springer Nature Switzerland AG CY - Cham AN - OPUS4-52612 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Auersch, Lutz A1 - Said, Samir T1 - Dynamic track-soil interaction – calculations and measurements about slab and ballast tracks N2 - The dynamic behaviour of slab and ballast tracks has been investigated by measurements and calculations. Hammer impacts and train passages have been analysed. Measurements have been performed by geophones (velocity transducers) which have been time-integrated to displacements. The calculations are done in frequency-wavenumber domain for multi-beam-on-continuous soil models. The characteristics of the different tracks and track elements have been established in theory and experiment. The frequency-dependent compliances (displacement transfer functions) show clear rail-on-rail-pad resonances or highly damped track-soil resonances. Compared to the rail and sleeper, the track plate has much lower amplitudes. The slab track has usually the highest rail amplitudes due to soft rail pads. The train passage yields track displacements which are a superposition of the axle loads from the two neighbouring axles of a bogie and from the two bogies of two neighbouring carriages. This global behaviour is characteristic for the track plate of the slab track whereas the rails of the slab and the ballast track behave more local with only one bogie of influence. The measurements agree very well with the theory of the continuous soil in case of the six measured slab tracks and acceptably well for the six measured ballast tracks. The measurements allow to find appropriate model parameters and to check the models, for example the Winkler model of the soil has been found less appropriate as it reacts more locally. KW - Slab track KW - Ballast track KW - Train passage KW - Hammer impact KW - Track-soil interaction PY - 2021 DO - https://doi.org/10.1631/jzus.A1900651 SN - 1673-565X VL - 22 IS - 1 SP - 21 EP - 36 PB - Zhejiang University Press CY - Hangzhou AN - OPUS4-52107 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Auersch, Lutz A1 - Said, Samir T1 - Slab track behaviour under train passage and hammer impact – Measurements at different sites and calculated track interaction with continuous soils N2 - This contribution intends to give an overview on the vibration behaviour of slab tracks in comparison of measurements and calculations and also by comparison of different track types at more than ten different measuring sites. In theory, tracks on continuous soil are calculated by the frequency-wavenumber domain method. In experiment, geophone measurements are transformed to displacement results. Two aspects of track behaviour are considered, the frequency-dependant compliance of the track, measured by hammer impact, and the deflection under a passing axle load. In theory, the response to a single axle can be calculated, whereas in experiment, only the passage of the whole train can be measured. For comparison of theory and experiment, the calculated deflection under a single axle is superposed to get the response of the whole train. As a result, the slab track characteristics are completely different from the ballast track characteristics where each axle can be seen in the time histories. The slab track has a more global behaviour where only a whole bogie can be found in the track response and moreover, the two neighbouring bogies are not completely separated. The measurement of the different track elements (rail, sleeper, track plate, base layer) and the frequency-dependant compliances with possible resonances yield further information About the properties of the track elements. The calculations show that the soil has the dominant influence on the amplitudes and the width of the track-plate displacements. In the measurement results, the following parameters are analysed: slab track vs. ballast track, different types of slab tracks, damaged slab tracks, different trains, switches at different measuring points, voided sleepers, an elastic layer, the mortar layer, and different soils at different places. Finally, a good agreement between measured and calculated results is found for the normal and some special (damaged, floating) slab tracks. KW - Slab track KW - Train passage KW - Hammer impact KW - Compliance function KW - Track deflection PY - 2020 UR - https://iiav.org/ijav/index.php?va=viewpage&vaid=177&id_number=95 DO - https://doi.org/10.20855/ijav.2020.25.31622 SN - 1027-5851 VL - 25 IS - 3 SP - 341 EP - 354 PB - International Institute of Acoustics and Vibration CY - Gliwice AN - OPUS4-51346 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Auersch, Lutz A1 - Said, Samir A1 - Rohrmann, R. T1 - Natural frequencies and modes of poles, beams, floors, road and rail bridges N2 - In the last three decades, the vibrations of many floors and bridges have been measured. The contribution shows some evaluation methods, experimental results and some modelling and theoretical results. Simple evaluation methods have been developed for single and coupled floors. Two coupled beams have been measured in good agreement with the theory. A more complex coupling model has been found for a large wooden floor in a castle consisting of six floor bays which correlates well with the measurements. Damaged and intact poles have been tested by their natural frequencies and damping values, and a fair correlation between the degree of damage and the shift of the frequency. Road bridges have been analysed in detail and some examples are presented. Railway bridges and trains are studied for resonant excitation. The risk of resonance can be estimated in frequency domain by using axle-sequence spectra of the train and the natural frequencies of the bridge. A measurement example shows the amplification, but even stronger the cancellation of the subsequent axle responses. Several high-speed trains and freight trains have been analysed for their potential resonance amplification. T2 - International Conference on Noise and Vibration Engineering (ISMA/USD 2020) CY - Online meeting DA - 07.09.2020 KW - Modalanalyse KW - Bauwerke KW - Bauteile KW - Brücken KW - Achsfolgespektren PY - 2020 SP - 1573 EP - 1585 PB - KULeuven CY - Leuven AN - OPUS4-51211 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hu, W.-H. A1 - Xu, Z.-M. A1 - Liu, M.-Y. A1 - Tang, D.-H. A1 - Lu, W. A1 - Li, Z.-H. A1 - Teng, J. A1 - Han, X.-H. A1 - Said, Samir A1 - Rohrmann, R. G. T1 - Estimation of the Lateral Dynamic Displacement of High-Rise Buildings underWind Load Based on Fusion of a Remote Sensing Vibrometer and an Inclinometer N2 - This paper proposes a novel method to estimate the lateral displacement of high-rise structures under wind loads. The coefficient β(x) is firstly derived, reflecting the relation between the structural lateral dynamic displacement and the inclination angle at the height x of a structure. If the angle is small, it is the ratio between the structural fundamental mode shape and its first-order derivative without influence of external loads. Several dynamic experiments of structures are performed based on a laser remote sensing vibrometer and an inclinometer, which shows that the fundamental mode is dominated in the structural displacement response under different types of excitations. Once the coefficient β(x) is curve-fitted by measuring both the structural lateral dynamic displacement and the inclination angle synchronously, the real-time structural lateral displacement under operational conditions is estimated by multiplying the coefficient β(x) with the inclination angle. The advantage of the proposed method is that the coefficient β(x) can be identified by lateral dynamic displacement measured in high resolution by the remote sensing vibrometer, which is useful to reconstruct the displacement accurately by the inclination angle under operational conditions KW - Inclination angle KW - High-rise building KW - Lateral dynamic displacement KW - Remote sensing vibrometer PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-506833 DO - https://doi.org/10.3390/rs12071120 VL - 12 IS - 7 SP - 1120 PB - MDPI CY - 4052 Basel, Schweiz AN - OPUS4-50683 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Herrmann, Ralf A1 - Hille, Falk A1 - Said, Samir A1 - Sterthaus, Jens A1 - Müller, Karsten A1 - Quercetti, Thomas A1 - Wille, Frank A1 - Paffenholz, J.-A. A1 - Baeßler, Matthias ED - Papadrakakis, M. ED - Fragiadakis, M. ED - Papadimitriou, C. T1 - Implementing a Structural Health Monitoring system using digital models of the BAM large drop test facility in Horstwalde N2 - At the Bundesanstalt für Materialforschung und -prüfung (BAM) full scale specimens for nuclear transport and storage containers (casks) are tested for their structural integrity in a series of drop tests on the Test Site Technical Safety in Horstwalde, 50 km south of Berlin. These drop tests cause a major stress not only on the casks, but also on the steel tower structure of the test facility, itself. The load pattern makes the structure very interesting for detailed investigation. The focus of the monitoring lies on the bolted joints of the flange connections that are a typical connection for cylindrical elements if welding is technical or economical unfavorable. The definition of the monitoring takes was done by investigating the existing documents and inspection results accompanied by building an initial digital representation of the structure, consisting of two finite element (FE) models and a geometrical 3D point cloud representation. As a first step the structures behavior during static and dynamic loading was analyzed using measurement data and an updated numerical FE Model. The idea behind is to use models for a digital planning and operation/evaluation of the structural health monitoring. A static FE simulation and a dynamic FE simulation are generated, to investigate how the structure behaves under the load conditions. T2 - XI International Conference on Structural Dynamics (EuroDyn 2020) CY - Online meeting DA - 23.11.2020 KW - Structural Health Monitoring KW - Drop Tests KW - System Identification KW - Digital Models KW - BIM PY - 2020 UR - https://generalconferencefiles.s3-eu-west-1.amazonaws.com/eurodyn_2020_ebook_procedings_vol1.pdf SN - 978-618-85072-0-3 VL - 1 SP - 1293 EP - 1304 PB - Institute of Structural Analysis and Antiseismic Research CY - Athen AN - OPUS4-51592 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hu, W.-H A1 - Tang, D.-H. A1 - Wang, M. A1 - Liu, J.-L. A1 - Li, Z.-H. A1 - Lu, W. A1 - Teng, J. A1 - Said, Samir A1 - Rohrmann, R. G. T1 - Resonance Monitoring of a Horizontal Wind Turbine by Strain-Based Automated Operational Modal Analysis N2 - A strain-based automated operational modal analysis algorithm is proposed to track the long-term dynamic behavior of a horizontal wind turbine under operational conditions. This algorithm is firstly validated by a scaled wind turbine model, and then it is applied to the dynamic strain responses recorded from a 5 MW wind turbine system. We observed variations in the fundamental frequency and 1f, 3f excitation frequencies due to the mass imbalance of the blades and aerodynamic excitation by the tower dam or tower wake. Inspection of the Campbell diagram revealed that the adverse resonance phenomenon and Sommerfeld effect causing excessive vibrations of the wind tower. KW - Strain KW - Automated operational modal analysis KW - Resonance KW - Horizontal wind turbine PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-503350 DO - https://doi.org/10.3390/en13030579 VL - 13 IS - 3 SP - 579 EP - 584 PB - MDPI CY - Schweiz, Basel AN - OPUS4-50335 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Simon, Patrick A1 - Schneider, Ronald A1 - Viefhues, Eva A1 - Said, Samir A1 - Herrmann, Ralf A1 - Baeßler, Matthias ED - Papadrakis, M. ED - Fragiadakis, M. ED - Papadimitriou, C. T1 - Vibration-based Structural Health Monitoring of a Reinforced Concrete Beam Subjected to Varying Ambient Conditions Using Bayesian Methods N2 - Inspection and maintenance contribute significantly to the lifetime cost of bridges. There is significant potential in using information obtained through structural health monitoring to update predictive models of the condition and performance of such structures, and thus ena-ble an improved decision-making regarding inspection and maintenance activities. Within the AISTEC project funded by the German Federal Ministry of Education and Research, we develop vibration-based structural health monitoring systems aimed at continuously provid-ing information on the structural condition of bridges. Environmental variations such as changing ambient temperatures can significantly influence the dynamic characteristics of bridges and thus mask the effect of structural changes and damages. It remains a challenge to account for such influences in structural health monitoring. To study the effect of ambient temperatures on the dynamic characteristics of beam structures, we monitor the vibration response of a reinforced concrete beam in the uncracked and cracked state at varying tem-peratures in a climate chamber. We postulate a set of competing parameterized probabilistic structural models, which explicitly account for the effect of varying ambient temperatures on the mechanical properties of the system. We then combine the information provided by the structural models with the information contained in the recorded vibration data to learn the parameters of the temperature-dependent structural models and infer the plausible state of the beam using Bayesian system identification and model class selection. T2 - EURODYN 2020, XI International Conference on Structural Dynamics CY - Online meeting DA - 23.11.2020 KW - Structural health monitoring KW - Bayesian methods KW - Environmental effects PY - 2020 SN - 978-618-85072-2-7 SN - 978-618-85072-0-3 SP - 1254 PB - Institute of Structural Analysis and Antiseismic Research, School of Civil Engineering, National Technical University of Athens (NTUA) CY - Athens, Greece AN - OPUS4-51590 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Said, Samir A1 - Auersch, Lutz T1 - Measurement of slab track behaviour at different sites N2 - Measured train passages and hammer impacts in combination with track-soil calculation have been successfully used for the detection of damaged slab tracks. This approach is now extended to intact slab and ballast tracks. The vibrations of many tracks have been measured at several levels from rail, sleeper, track plate, base plate, base layer to the subsoil by velocity or acceleration sensors. The time histories have to be integrated once or twice to get the displacements. The displacement signals include an arbitrary time-dependent shift which must be eliminated or respected in the interpretation. On the other hand, the calculation of slab and ballast tracks have been done in frequency-wavenumber domain. The displacements along the track and the frequency-dependent compliance transfer functions can be calculated. The latter can be compared with the results of the hammer impacts on the track. The deformation of the track can be transformed to time histories for a whole train and compared to the measured train passages. Many slab (and ballast) tracks have been measured at different sites. The displacements of the tracks are presented, and the following parameters have been analysed in the measurement results: slab track vs. ballast track, different types of slab tracks, damaged slab tracks, different trains, switches at different measuring points, an elastic layer, the mortar layer, different soils at different places. The soil should have the dominant influence on the track-plate displacements. Slab and ballast track yield also big differences in maximum displacement and width of deformation. Some of the preceding aspects will be analysed in comparison of measurement and theory. T2 - 26th International Congress on Sound and Vibration (ICSV26) CY - Montreal, Canada DA - 07.07.2019 KW - Displacements KW - Train passage KW - Slab track KW - Hammer impact KW - Vibration measurements PY - 2019 AN - OPUS4-48495 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Auersch, Lutz A1 - Said, Samir T1 - Measurement of slab track behaviour at different sites N2 - Measured train passages and hammer impacts in combination with track-soil calculation have been successfully used for the detection of damaged slab tracks. This approach is now extended to intact slab and ballast tracks. The vibrations of many tracks have been measured at several levels from rail, sleeper, track plate, base plate, base layer to the subsoil by velocity or acceleration sensors. The time histories have to be integrated once or twice to get the displacements. The displacement signals include an arbitrary time-dependent shift which must be eliminated or respected in the interpretation. On the other hand, the calculation of slab and ballast tracks have been done in frequency-wavenumber domain. The displacements along the track and the frequency-dependent compliance transfer functions can be calculated. The latter can be compared with the results of the hammer impacts on the track. The deformation of the track can be transformed to time histories for a whole train and compared to the measured train passages. Many slab (and ballast) tracks have been measured at different sites. The displacements of the tracks are presented, and the following parameters have been analysed in the measurement results: slab track vs. ballast track, different types of slab tracks, damaged slab tracks, different trains, switches at different measuring points, an elastic layer, the mortar layer, different soils at different places. The soil should have the dominant influence on the track-plate displacements. Slab and ballast track yield also big differences in maximum displacement and width of deformation. Some of the preceding aspects will be analysed in comparison of measurement and theory. T2 - 26th International Congress on Sound and Vibration (ICSV26) CY - Montreal, Canada DA - 07.07.2019 KW - Displacements KW - Slab track KW - Train passage KW - Hammer impact KW - Vibration measurements PY - 2019 SN - 978-1-9991810-0-0 SN - 2329-3675 SP - T15RS01_316_1 EP - T15RS01_316_8 PB - Canadian Acoustical Association CY - Montreal, Kanad AN - OPUS4-48498 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Teng, Jun A1 - Tang, De-Hui A1 - Zhang, Xiao A1 - Hu, Wei-Hua A1 - Said, Samir A1 - Rohrmann, Rolf G. T1 - Automated modal analysis for tracking structural change during construction and operation phases N2 - The automated modal analysis (AMA) technique has attracted significant interest over the last few years, because it can track variations in modal parameters and has the potential to detect structural changes. In this paper, an improved density-based spatial clustering of applications with noise (DBSCAN) is introduced to clean the abnormal poles in a stabilization diagram. Moreover, the optimal system model order is also discussed to obtain more stable poles. A numerical Simulation and a full-scale experiment of an arch bridge are carried out to validate the effectiveness of the proposed algorithm. Subsequently, the continuous dynamic monitoring system of the bridge and the proposed algorithm are implemented to track the structural changes during the construction phase. Finally, the artificial neural network (ANN) is used to remove the temperature effect on modal frequencies so that a health index can be constructed under operational conditions. KW - Automated Modal Analysis for Tracking Structural Change during Construction and Operation Phases PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-475116 UR - https://www.mdpi.com/1424-8220/19/4/927/pdf DO - https://doi.org/10.3390/s19040927 SN - 1424-8220 VL - 19 IS - 4 SP - 927, 1 EP - 23 PB - MDPI AG CY - Basel, Switzerland AN - OPUS4-47511 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Said, Samir A1 - Auersch, Lutz T1 - Prediction of explosion-induced ground and building vibrations - measured wave velocities, transfer functions and attenuation N2 - Explosion-induced ground vibrations have been measured at several places. Results about the wave propagation are shown in this contribution. The particle velocities of the soil have been measured at up to 1000 m distance from the explosion and are presented as time records (seismograms) and one-third octave band spectra (transfer functions). The results are compared with the results of hammer impacts. The seismograms clearly show different wave types, compressional waves of the air, the water and the soil, and the Rayleigh wave. The hammer impacts yield good results up to 100 m and incorporate higher frequencies at about 50 Hz, whereas the explosion results in a ground vibration with frequencies around 10 Hz and a longer range of influence. Explosion and hammer excitations are evaluated for the wave velocities of the soil by using the wavenumber and the spatial auto-correlation method. The attenuation of the ground vibration amplitudes A with distance r can well be presented by a power law A ~ r -q. This type of amplitude-distance law and the corresponding power q > 1 are substantiated in the contribution. The influence of the charge weight W is evaluated as an additional power law A ~ W -p for each measuring site. The power is found quite similarly around q  0.6 as all sites have a medium soft soil such as sand and clay. The obtained amplitude-charge-distance law can be used to predict the explosion-induced ground and building vibrations at other sites. T2 - International Congress on Sound and Vibration (ICSV25) CY - Hiroshima, Japan DA - 08.07.2018 KW - Prediction of explosion induced ground and building vibration KW - Explosion-induced ground vibrations KW - Hammer impact KW - Soil properties KW - Amplitude-distance laws KW - Amplitude-charge weight laws PY - 2018 SN - 978-83-7880-552-6 SN - 2329-3675 SP - 1 EP - 8 PB - Silesian University of Technology Press CY - Gliwice, Poland AN - OPUS4-45506 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Auersch, Lutz A1 - Said, Samir ED - Bian, Xuecheng ED - Chen, Y. ED - Ye, X. T1 - Vibration measurements for the control of damaged and repaired railway tracks N2 - This contribution presents experimental methods to detect track damage. At BAM (Federal Institute of Material Research and Testing), a measuring car with a measuring system of 72 channels, geophones, mountings, cables, harmonic and impulsive exciters is used for dynamic measurements of the track, the soil and buildings. An instrumented hammer allows force measurements and to evaluate transfer functions of the track, and the soil. Wave measurements are used to identify the soil characteristics. Train passages are measured at the track and for the train induced ground vibrations. In addition to these in situ options, tests of tracks or track elements can be performed in a large laboratory. KW - Track vibration KW - Track damage PY - 2018 SN - 978-981-10-4507-3 DO - https://doi.org/10.1007/978-981-10-4508-0_2 SP - 13 EP - 30 PB - Springer CY - Singaporer AN - OPUS4-45457 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Said, Samir A1 - Auersch, Lutz T1 - Prediction of explosion-induced ground and building vibrations - measured wave velocities, transfer functions and attenuation N2 - Explosion-induced ground vibrations have been measured at several places. Results about the wave propagation are shown in this contribution. The particle velocities of the soil have been measured at up to 1000 m distance from the explosion and are presented as time records (seismograms) and one-third octave band spectra (transfer functions). The results are compared with the results of hammer impacts. The seismograms clearly show different wave types, compressional waves of the air, the water and the soil, and the Rayleigh wave. The hammer impacts yield good results up to 100 m and incorporate higher frequencies at about 50 Hz, whereas the explosion results in a ground vibration with frequencies around 10 Hz and a longer range of influence. Explosion and hammer excitations are evaluated for the wave velocities of the soil by using the wavenumber and the spatial auto-correlation method. The attenuation of the ground vibration amplitudes A with distance r can well be presented by a power law A ~ r -q. This type of amplitude-distance law and the corresponding power q > 1 are substantiated in the contribution. The influence of the charge weight W is evaluated as an additional power law A ~ W -p for each measuring site. The power is found quite similarly around q  0.6 as all sites have a medium soft soil such as sand and clay. The obtained amplitude-charge-distance law can be used to predict the explosion-induced ground and building vibrations at other sites. T2 - International Congress on Sound and Vibration (ICSV25) CY - Hiroshima, Japan DA - 08.07.2018 KW - Soil properties KW - Amplitude-charge weight laws KW - Amplitude-distance laws KW - Explosion-induced ground vibrations KW - Hammer impact KW - Prediction of explosion induced ground and building vibration PY - 2018 AN - OPUS4-45508 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hu, Wei-Hua A1 - Tang, De-Hui A1 - Teng, Jun A1 - Said, Samir A1 - Rohrmann, Rolf T1 - Structural health monitoring of a prestressed concrete bridge based on statistical pattern recognition of continuous dynamic measurements over 14 years N2 - This work describes a vibration-based structural health monitoring of a prestressed-concrete box girder bridge on the A100 Highway in Berlin by applying statistical pattern recognition technique to a huge amount of data continuously collected by an integrated monitoring system during the period from 2000 to 2013. Firstly, the general condition and potential damage of the bridge is described. Then, the dynamic properties are extracted from 20 velocity sensors. Environmental variability captured by five thermal transducers and traffic intensity approximately estimated by strain measurements are also reported. Nonlinear influences of temperature on natural frequencies are observed. Subsequently, the measurements during the first year are used to build a baseline health index. The multiple linear regression (MLR) method is used to characterize the nonlinear relationship between natural frequencies and temperatures. The Euclidean distance of the residual errors is calculated to build a statistical health index. Finally, the indices extracted from the following years gradually deviate; which may indicate structural deterioration due to loss of prestress in the prestressed tendons. KW - Bridge KW - Structural health monitoring KW - Statistical pattern recognition KW - Temperature effect PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-468126 DO - https://doi.org/10.3390/s18124117 SN - 1424-8220 VL - 18 IS - 12 SP - 4117, 1 EP - 28 PB - MDPI CY - 4052 Basel, Schweiz AN - OPUS4-46812 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Auersch, Lutz A1 - Said, Samir T1 - Track-soil dynamics – calculation and measurement of damaged and repaired slab tracks N2 - The damage detection and repair control have become important tasks for ballast and slab tracks. Measurements which compare the damaged and the repaired status of the same track section at different times, or which compare a damaged and an intact track section at the same time, have been successfully performed at some sites in Germany. The loss of contact between the sleeper and the track plate, between the track plate and the base plate, and between the base plate and the base layer have been analysed. The soil properties of each site have been measured and have been used to establish realistic track-soil models. Theoretical results of the wavenumber domain and the finite-element boundary element method have been compared with the experimental results. The observed experimental and theoretical results, changes in the time histories of displacements and velocities due to train passages and in the transfer functions (receptances) due to hammer impacts, are encouraging that these measurements can be used to detect track damage. KW - Railway track KW - Slab track KW - Track-soil interaction KW - Field tests KW - Track damage KW - Monitoring KW - Finite element method KW - Boundary element method PY - 2017 DO - https://doi.org/10.1016/j.trgeo.2017.06.003 SN - 2214-3912 VL - 12 IS - September SP - 1 EP - 14 PB - Elsevier CY - London AN - OPUS4-42581 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CHAP A1 - Luong, Thi Mai Hoa A1 - Lorenz, W. A1 - Rohrmann, R.G. A1 - Zabel, V. A1 - Said, Samir ED - Springer, Cham, T1 - Finite Element Model Calibration of a Historic Wiegmann–Polonceau Truss Based on Experimental Modal Parameters N2 - This paper describes the experimental calibration of an existing Wiegmann–Polonceau roof truss based on modal parameters. Dynamic tests allowed the determination of the natural frequencies and mode shapes of the global truss and of individual truss members. The global and local modal configurations as well as coupled vibration of truss members are discussed. In addition, as truss members are axially loaded, the effect of stress stiffening on the modal parameters is considered. Moreover, several finite element models with different modelling assumptions for the details of the connections and member geometrical characteristics such as gusset plates and turnbuckles were developed. A suitable numerical model was chosen to represent the truss structural behavior. This paper focuses on the local measurement and analysis strategies applied to single truss members. The possibility of using a local analysis method, namely methods that consider individual members as part of a structure, is demonstrated to assess the behavior of the global truss structure. The comparison of the results after calibration reveals a very good correlation between the experimentally identified and numerically estimated modal parameters of the historic truss. KW - Modal parameters KW - Axial force KW - Dynamic test KW - Finite element method KW - Truss structures PY - 2017 SN - 978-3-319-67443-8 DO - https://doi.org/10.1007/978-3-319-67443-8_18 SN - 2366-2557 VL - 5 SP - 212 EP - 224 PB - Springer International Publishing ET - 1 AN - OPUS4-42524 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Auersch, Lutz A1 - Said, Samir A1 - Zhu, Shaocheng T1 - Dynamic testing of track damage before and after construction, after damage and after repair N2 - The Federal Institute of Material Research and Testing (BAM) has collected some experience with the testing of damaged, repaired and newly constructed railway tracks. The experimental methods are hammer testing of the track at different positions, hammer testing of the soil, measurement of train passages, and in all cases, measurements with geophones at different positions. The measured signals are evaluated for wave velocities (dispersion of the soil or the track-soil system), for transfer functions (transfer admittances of the soil, compliances of the track in amplitude and phase), and one-third octave band spectra of the track response to hammer and train excitation. These methods are applied at different stages of the track construction. Before track construction, wave velocities and transfer functions of the sub-soil can indicate problems with soft soils. After track construction, a check of the acceptable state of the track can be done by comparison of many excitation positions and track sites. After a track damage (a lose sleeper or a lose plate of a slab track) and after its repair, the sensitivity of the different measurement quantities to different track errors and the achieved improvement of the repair can be determined. The contribution shows examples of all these track situations T2 - Int. Conf. on Rail Transportation CY - Chengdu, China DA - 10.07.2017 KW - Track damage KW - Dynamic testing KW - Hammer tests KW - Train passages PY - 2017 AN - OPUS4-42490 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hu, W.-H. A1 - Said, Samir A1 - Rohrmann, R. A1 - Cunha, À. A1 - Teng, J. T1 - Continuous dynamic monitoring of a prestressed concrete bridge based on strain, inclination and crack measurements over a 14-year span N2 - The Westend Bridge is located on the A100 Highway in Berlin. An integrated continuous dynamic monitoring system, composed of 20 velocity sensors, 5 temperature sensors, 3 strain gauges, 1 crack sensor and 2 inclination sensors, was implemented by the Federal Institute for Materials Research and Testing in 2000. The system runs continuously with occasional intermittence and led to a huge amount of data over a 14-year span. In this article, variations of the strain, crack and inclination measurements during the last 14 years are presented. It is noted that the observed crack and inclination of the bridge are strongly influenced by seasonal temperature variation. It further induces change in the relationship between the strains measured in both concrete and prestressed tendon. Application of k-means cluster Analysis technique in both the crack and strain measurements can partition them into different seasonal phases by identifying ‘turning points’ that indicate annual periodical bridge change. In the period of these two ‘turning points’, a strong linear relation of the strains in two materials is observed. In the rest of the year, a nonlinear relationship between the strains recorded in both the concrete and the prestressed tendon is noted. The possible reason is the additional thermal load due to the change in temperature difference between the bridge’s surface and soffit. Finally, a health index in a Framework of regression model and process control theory is proposed by investigating the linear relationship between the strains in concrete and prestressed tendon. The tendency of the health index in the 14 years may suggest the long-term bridge change during that time frame. KW - Detection of structural change KW - Structural health monitoring KW - Strain KW - Crack KW - Inclination KW - Bridge PY - 2017 DO - https://doi.org/10.1177/1475921717735505 VL - 17 IS - 5 SP - 1073 EP - 1094 PB - SAGE CY - USA/UK AN - OPUS4-45990 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Auersch, Lutz A1 - Said, Samir T1 - Dynamic testing of tracks and track sites before and after construction, after damage and after repair N2 - The Federal Institute of Material Research and Testing (BAM) has collected some experience with the testing of damaged, repaired and newly constructed railway tracks. The experimental methods are hammer testing of the track at different positions, hammer testing of the soil, measurement of train passages, and in all cases, measurements with geophones at different positions. The measured signals are evaluated for wave velocities (dispersion of the soil or the track-soil system), for transfer functions (transfer admittances of the soil, compliances of the track in amplitude and phase), and one-third octave band spectra of the track response to hammer and train excitation. These methods are applied at different stages of the track construction. Before track construction, wave velocities and transfer functions of the sub-soil can indicate problems with soft soils. After track construction, a check of the acceptable state of the track can be done by comparison of many excitation positions and track sites. After a track damage (a lose sleeper or a lose plate of a slab track) and after its repair, the sensitivity of the different measurement quantities to different track errors and the achieved improvement of the repair can be determined. The contribution shows examples of all these track situations. T2 - First International Conference on Rail Transportation CY - Chengdu, China DA - 10.7.2017 KW - Track damage KW - Dynamic testing KW - Hammer tests KW - Train passages PY - 2017 SP - 1 EP - 9 PB - Southwest Jiaotong University CY - Chengdu, China AN - OPUS4-42090 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Auersch, Lutz A1 - Said, Samir A1 - Müller, Roger T1 - Measurements on the vehicle-track interaction and the excitation of railway-induced ground vibration N2 - Two railway measurement campaigns have been performed in Germany and Switzerland which yield insight in the vehicle-track-soil interaction. The campaign in Germany has included simultaneous measurement of vehicle, track, and soil vibrations during train runs with 16, 25, 40, 63, 80, 100, 125, 140, 160 km/h, and impulse measurements of the passenger car, three track sections and the soil. Two ballast tracks, one on the soil surface and one on a concrete bridge, have been investigated as well as a slab track in a tunnel. Ten different sites in Switzerland have been measured for soil properties and train-induced ground vibrations, which allow to determine the excitation forces of the railway traffic. New axle-box measurements at some of the Swiss sites have been analysed to get further experimental evidence. All these measurements have been evaluated to characterize the excitation processes. Relations between vehicle vibration and ground vibration can be observed. The vehicle vibrations, namely the accelerations of the wheelsets, yield the dynamic forces due to the passage over the irregularities of the vehicle and the track. The ground vibrations are correlated to these dynamic forces to a certain extent. Some mid-frequency ground vibration amplitudes, however, are higher than expected from the dynamic excitation forces. The experimental observations can be explained by an irregular response to the passage of the static loads, that means the passage of the static loads over an irregular ballast or soil. This correct understanding of the excitation processes is important for the prediction as well as for the mitigation of railway induced ground vibrations. T2 - X INTERNATIONAL CONFERENCE ON STRUCTURAL DYNAMICS (EURODYN 2017) KW - Vehicle-track interaction KW - Ground vibration KW - Track vibration KW - Railway measurement campaign KW - Axle box measurements PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-420889 DO - https://doi.org/10.1016/j.proeng.2017.09.390 SN - 1877-7058 VL - 199 SP - 2615 EP - 2620 PB - Elsevier CY - London AN - OPUS4-42088 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hu, W.‐H. A1 - Álvaro Cunha, Á. A1 - Caetano, E. A1 - Rohrmann, R. G. A1 - Said, Samir A1 - Teng, J. T1 - Comparison of different statistical approaches for removing environmental/operational effects for massive data continuously collected from footbridges N2 - The implementation of continuous dynamic monitoring systems in two bridges, in Portugal, is enabled to detect the occurrence of very significant environmental and operational effects on the modal properties of these bridges, based on automated processing of massive amounts of monitoring data collected by a set of accelerometers and thermal sensors over several years. In order to remove or mitigate such environmental/operational effects with the purpose of damage detection, two different statistical methods have been adopted. One of them is the multiple linear regression by performing nonlinear correlation analysis between measured modal properties and environmental/operational variables. Another one is principal component regression based on the identification of the linear subspace within the modal properties without using measured values of environmental and operational variables. This paper presents a comparison of the performance of these two alternative approaches on the basis of continuous monitoring data acquired from two instrumented bridges and simulated damage scenarios. It is observed that different methods show similar capacity in removing environmental effects, and the multiple linear regression method is slightly more sensitive to structural damage. KW - Multiple linear KW - Damage detection KW - Environmental/operational effect KW - Modal property PY - 2017 DO - https://doi.org/10.1002/stc.1955 SN - 1545-2255 VL - 24 IS - 8 SP - e1955-1 EP - e1955-19 PB - John Wiley & Sons, Ltd AN - OPUS4-41147 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Said, Samir A1 - Auersch, Lutz T1 - Vibration measurements for the control of damaged and repaired railway tracks N2 - Measurements comparing the damaged and the repaired status of the same track section at different times, or a damaged and an intact track section at the same time have been successfully performed and compared with the theoretical behavior of intact and damaged tracks. The loose of contact between the sleeper and the plate, between the plate and the base layer, due to train passages and hammer impacts, have been investigated. T2 - 7th International Symposium on Environmental Vibration and Transportation Geodynamics CY - Hangzhou, China DA - 28.10.2016 KW - Railway track KW - Slab track KW - Field tests KW - Track damage monitoring KW - Finite element method KW - Boundary element method PY - 2016 AN - OPUS4-38275 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Auersch, Lutz A1 - Said, Samir T1 - Vibration measurements for the control of damaged and repaired railway tracks N2 - The damage detection and repair control have become important tasks for ballast and slab tracks. Measurements which compare the damaged and the repaired status of the same track section at different times, or which compare a damaged and an intact track section at the same time, have been successfully performed at some sites in Germany with slab tracks and ballast tracks and compared with the theoretical behaviour of intact and damaged tracks. The loss of contact between the sleeper and the plate, between the plate and the base layer, and some problems with soft or weakened soil have been analysed. The observed results, changes in the time histories of displacements and velocities due to train passages and in the transfer functions (compliances) due to hammer impacts, are encouraging that these measurements can be used to detect track damage. In addition, calculations with the combined finite-element boundary-element method have been used to confirm the conclusions about intact or damaged railway tracks. T2 - 7th International Symposium on Environmental Vibration and Transportation Geodynmaics CY - Hangzhou, China DA - 28.10.2016 KW - Railway track KW - Slab track KW - Ballast track KW - Track-soil interaction KW - Field tests KW - Track damage monitoring KW - Finite element method KW - Boundary element method PY - 2016 SP - 3 EP - 19 AN - OPUS4-38261 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Said, Samir T1 - Structural health monitoring by division 7.2, buildings and structures N2 - BAM is one of the pioneers in Germany and Europe regarding the monitoring of civil structures. BAM-Division 7.2 operates its monitoring systems with sophisticated components for data acquisition and data analysis, which can be flexibly adapt to the respective structure and measuring tasks. The BAM monitoring systems have been operated on numerous bridges (steel, concrete, pre-stressed concrete and masonry), buildings, towers, masts, monuments, wind turbines and other structures. In 1999, BAM established a national standard 'Automated continuous monitoring in civil engineering'. This has been internationalized within the framework of the EU research project SAMCO "F08b Guideline for Structural Health Monitoring". BAM-Division 7.2 is interested in international cooperation with Chinese partners. T2 - SEMINARS AT SHENZHEN GRADUATE SCHOOL OF HIT CY - Shenzhen, China DA - 02.11.2016 KW - Structural health monitoring (SHM) KW - Load-carrying capacity KW - Structural analyses KW - Damage detection PY - 2016 AN - OPUS4-38277 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hu, W. A1 - Said, Samir A1 - Rohrmann, R. A1 - Teng, J. A1 - Li, Z. A1 - Lu, W. A1 - Cunha, A. T1 - Operational modal analysis and continuous dynamic monitoring of structures N2 - This paper addresses operational modal analysis (OMA) and continuous dynamic monitoring (CDM) of two bridges. One of them is installed with Tuned Mass Dampers (TMDs) while another one is a normal bridge. Two ambient vibration tests were performed on these two bridges respectively. It is observed that not only installation of TMDs but also environmental factors influence the variations of structural frequencies, which may mask the subtle change induced by small structural changes. As a result, continuous dynamic monitoring systems were implemented on these two bridges, in order to evaluate efficiency of the TMD system, remove the environmental effects and build reliable damage indices that are only sensitive to structural changes. The results of CDM of these two bridges during several years are presented. Software systems developed for OMA and CDM are also introduced. T2 - 14th International Symposium on Structural Engineering (ISSE-14) CY - Beijing, Peoples Republic of China DA - 12.10.2016 KW - Structure KW - Operational modal analysis KW - Continuous dynamic monitoring PY - 2016 SN - 978-7-03-050125-7 VL - 2016 SP - 366 EP - 372 PB - Science Press Beijing AN - OPUS4-38876 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Auersch, Lutz A1 - Said, Samir T1 - Methods and phenomena of single and coupled floor vibrations - Measurements in apartment and office buildings N2 - A survey of the phenomena and methods for floor vibrations is presented. Experimental results of floor vibrations are shown for many floors in six different buildings. The signals have been evaluated for waves and modes by simple procedures. General rules have been established between the material and the area of a specific floor, and its local eigenfrequency. The damping values of the floor vibrations have been found between D = 1 and 10 % where somewhat higher values have been measured for wooden floors, and a weak correlation with the eigenfrequency has been established. The velocities of bending waves propagating in a storey and the attenuation with distance in the building have been analysed. A considerable transfer of vibration from one room to far away parts of the building has been found in the studied buildings with concrete and wooden floors. An example building has been analysed for modes of coupled floor bays. The strong coupling of similar neighbouring floor bays would yield a wide band of global resonance frequencies. The measured wooden floor exhibits a weak coupling of the neighbouring floor bays and a narrower band of eigenfrequencies. A special method has been tested with the impulse measurements to estimate the coupled eigenmodes in presence of the high damping. From the ambient measurement, a low-frequency vibration mode has been detected which includes the vibration of the whole building and the soil. The coupling of floors to other floors and the whole building is an important phenomenon of structural dynamics which should be observed for the prediction of vibration due to internal and external sources. PY - 2015 SN - 1351-010X VL - 22 IS - 2 SP - 81 EP - 108 PB - Multi-Science Publ. Co. CY - Brentwood AN - OPUS4-34839 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hu, Wei-Hua A1 - Thöns, Sebastian A1 - Rohrmann, Rolf A1 - Said, Samir A1 - Rücker, Werner T1 - Vibration-based structural health monitoring of a wind turbine system. Part I: Resonance phenomenon N2 - This paper is focused on a resonance phenomenon of a wind turbine system in 5 MW class, on the basis of dynamic signals acquired continuously from the tubular tower under normal operational conditions during two years. Firstly, technique specifications of the wind turbine system are introduced and a finite element model is developed to characterize the structural dynamic properties. The following part describes the continuous dynamic monitoring system integrated with an automated operational modal analysis procedure using the poly-reference Least Squares Complex Frequency domain (p-LSCF) method. Subsequently, variations and mutual relationships of environmental/operational factors such as vibration amplitude, temperature, wind speed, rotation speed of blades, pitch angle and nacelle direction are also presented. Finally, significant resonance is observed due to the fundamental frequency of the tower matching with the harmonic frequency induced by the rotation of three blades. As the rotation speed of rotor approaches to 8 rpm, the vibration amplitude of the tower increases significantly and the corresponding damping value decreases. With the further rising wind velocity, the rotation speed of blades stops increasing and the input energy just contribute to accumulate the vibration amplitude of tower. Such observation indicates the Sommerfeld effect that aggravates the resonance phenomenon. A vibration control device is necessary to minimize the excessive structural responses. A companion paper will further discuss the environmental/operational effects on dynamic properties of the wind turbine system under the operational conditions. KW - Vibration KW - Structural health monitoring KW - Wind turbine KW - Automated operational modal analysis KW - Resonance KW - Sommerfeld effect PY - 2015 DO - https://doi.org/10.1016/j.engstruct.2014.12.034 SN - 0141-0296 VL - 89 SP - 260 EP - 272 PB - Elsevier Ltd. CY - Oxford AN - OPUS4-32878 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hu, Wei-Hua A1 - Thöns, Sebastian A1 - Rohrmann, Rolf A1 - Said, Samir A1 - Rücker, Werner T1 - Vibration-based structural health monitoring of a wind turbine system. Part II: Environmental/operational effects on dynamic properties N2 - The second part of these companion papers mainly researches environmental/operational influences on structural dynamic properties under normal operational conditions during two years, in order to extract a statistical based damage-sensitive indicator for health monitoring of a wind turbine system. The correlation analyses between experimental identified frequencies, damping values as well as mode shapes and environmental/operational factors such as rotation speed of blades, wind speed, pitch angle, temperature and nacelle direction are presented. It is observed that the frequency estimates are influenced by the nacelle position, the activation of rotor, the rotation speed of blades and the wind speed as well as the temperature. Regarding to the damping estimates, they are mainly associated with variation of the aerodynamic damping due to the increasing wind speed. Besides, the resonance phenomenon is also observed in higher modes. The harmonic frequencies due to blades passing by tower are found and the corresponding damping value decreases. Moreover, the mode shapes in some modes are strongly affected by the position of the nacelle. Subsequently, two types of simulated damage including the reduction of stiffness in both the rotor blade and the tubular tower are successfully detected by applying the Principal Component Analysis (PCA) based methods to these temperature-sensitive frequency estimates. Comparison of change of the extracted health features indicates that they are more sensitive with the tower damage. KW - Vibration KW - Structural health monitoring KW - Wind turbine KW - Environmental/operational effects KW - Modal properties KW - Principal Component Analysis KW - Novelty analysis KW - Damage detection KW - Sommerfeld effect KW - Automated operational modal analysis KW - Resonance PY - 2015 DO - https://doi.org/10.1016/j.engstruct.2014.12.035 SN - 0141-0296 VL - 89 SP - 273 EP - 290 PB - Elsevier Ltd. CY - Oxford AN - OPUS4-32879 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Auersch, Lutz A1 - Said, Samir T1 - Comparison of different dispersion evaluation methods and a case history with the inversion to a soil model, related admittance functions, and the prediction of train-induced ground vibration N2 - Ground vibrations due to different technical sources are analysed in theory and experiment for the dispersion of Rayleigh waves and the admittance spectra. Both tasks are theoretically based on the same concept: The admittance function in frequency–wavenumber domain yields the dispersion as its maxima, and the admittance function in space domain is obtained by integrating it over the wavenumbers. On the experimental side, many signal processing methods have been applied to many sites and have been developed by the authors in the last 35 years, i.e., time-domain methods, including the cross-correlation method, and frequency-domain methods such as the spectral analysis of surface waves with two or multiple sensors, the wavenumber-transform method, and the spatial autocorrelation method. All methods are presented by their basic formula and by at least one example site. Different sensor arrays and deterministic and stochastic sources have been tested for the spatial autocorrelation method and the wavenumber-transform method at several sites. In addition, all frequency-domain methods are presented for a specific layered site comparing their quality. The evaluated dispersion curves are very similar, but a somewhat higher frequency range has been found for the fastest method, i.e., the multi-sensor spectral-analysis-of-surface-waves method. The theoretical solutions have been used for the inversion of the measured dispersion to the soil profile of the specific layered soil. The theoretical soil model has subsequently been used to predict the ground vibration spectra of hammer and railway excitation that exhibit a good agreement with the corresponding measurements. Thus, the contribution shows the benefit of active and passive seismic methods for the prediction of railway vibration, including a new version of the spatial autocorrelation method for technical vibrations. On the other hand, technical and namely railway vibrations are considered a seismic source for the exploration of near surface soils. PY - 2015 DO - https://doi.org/10.3997/1873-0604.2015011 SN - 1569-4445 VL - 13 IS - 2 SP - 127 EP - 142 PB - EAGE - European Association of Geoscientists & Engineers CY - Houten AN - OPUS4-33836 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hu, Wei-Hua A1 - Said, Samir A1 - Rohrmann, Rolf A1 - Rücker, Werner A1 - Cunha, A. A1 - Rogge, Andreas ED - De Stefano, A. T1 - Vibration-based structural health monitoring of a highway bridge based on continuous dynamic measurements during 14 years N2 - This paper presents the continuous dynamic measurements of an aging prestressed box-beam bridge during the period from 2000 to 2013, which consists of dynamic properties and environmental/operational factors, as well as the Variation of the extracted health features after removing the environmental/operational effects. Firstly, the variations of frequency estimates, temperatures and traffic loads from 2000 to 2013 are described. Subsequently, correlation analysis between them indicates the nonlinear influences of the temperature on the frequency estimates. The Multiple Linear Regression (MLR) method is used to remove the environmental/operational effects and the health index is proposed by performing the Novelty Detection analysis of the residual errors. Finally, the variations of the health index may indicate clear structural modifications that can be also characterized by the long term monitoring of the dynamic strain in the prestressed cable. T2 - SHMII-7 - 7th International conference on structural health monitoring of intelligent infrastructure CY - Torino, Italy DA - 01.07.2015 KW - Westend bridge PY - 2015 SP - 1 EP - 12 AN - OPUS4-35124 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hu, Wei-Hua A1 - Thöns, Sebastian A1 - Said, Samir A1 - Rücker, Werner ED - Cunha, A. ED - Caetano, E. ED - Ribeiro, P. ED - Müller, G. T1 - Resonance phenomenon in a wind turbine system under operational conditions N2 - A prototype of wind turbines in 5 megawatt dass was built and tested at the first German offshore wind energy test fteld in the North Sea. In order to investigate dynamic behaviors under a complex state of loads, a continuous dynamic monitoring System was implemented by Federal Institute for Material Research and Testing (BAM). It recorded structural responses and environmental/operational variables from November 2007 to October 2009. This paper presents significant resonance phenomenon due to the interaction in the tower-nacelle System under operational conditions. Modal parameters are automatically estimated by the poly reference Least Square Complex Frequency domain (p-LSCF) method. Campbell plot demonstrates that a three-blade passage frequency and its multiples f3n match with the natural frequencies of the wind turbine System in several modal Orders. The damping estimates decrease and the Vibration amplitude increase significantly. A control System is necessary to minimize the excessive vibrations. T2 - EURODYN 2014 - 9th International conference on structural dynamics CY - Porto, Portugal DA - 30.06.2014 KW - Wind turbine KW - Tower-nacelle system KW - Resonance KW - Continuous dynamic monitoring KW - Automated operational modal analysis PY - 2014 SN - 978-972-752-165-4 SN - 2311-9020 SP - 3619 EP - 3626 AN - OPUS4-32970 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hu, Wei-Hua A1 - Said, Samir A1 - Rohrmann, Rolf A1 - Rücker, Werner A1 - Cunha, A. T1 - Continuous dynamic monitoring of structures N2 - This paper presents the development of a continuous dynamic monitoring System and its applications to different structures, with the purpose of understanding structural real behaviours under operational conditions and detecting early structural modifications. The first part of paper introduces a complete continuous dynamic System, consists of signal acquisition and communication, automated signal processing and management, investigation of the interaction between structures and its environmental/operational conditions, feature extraction and detection of structural modification. The rest of paper describes the applications of continuous dynamic monitoring System to different structures such as a wind turbine System and a highway bridge. T2 - 13th International symposium on structural engineering (ISSE'13) CY - Hefei, China DA - 24.10.2014 KW - Continuous dynamic monitoring KW - Automated system identification KW - Environmental/operational effects KW - Resonance KW - Feature extraction KW - Structural modification PY - 2014 SN - 978-7-09-042032-9 SP - 1922 EP - 1933 PB - Science Press AN - OPUS4-32971 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Auersch, Lutz A1 - Said, Samir A1 - Knothe, Esther A1 - Rücker, Werner ED - Cunha, A. ED - Caetano, E. ED - Ribeiro, P. ED - Müller, G. T1 - The dynamic behavior of railway tracks with under sleeper pads, finite-element boundary-element model calculations, laboratory tests and field measurements N2 - A variety of isolation measures exists to reduce the vibration in the neighbourhood of railway lines. They can be roughly classified as elastic or stiffening systems. There are the following elastic elements, rail pads or resilient fixation systems between rail and sleeper, under sleeper pads or sleeper shoes under the sleepers, and ballast mats under the ballast. Stiffening systems (plates) are used as slab tracks, floating slab tracks, or mass-spring systems. In the EU project “Railway induced vibration abatement solutions (RIVAS)”, elastic under sleeper pads have been investigated. The dynamic behaviour of the track and the surrounding soil has been calculated by the combined finite-element boundary-element method in a systematic parameter study. It has been shown that the mitigation effect can be improved by soft under sleeper pads or by heavy sleepers. Consequently, such track elements (soft under sleeper pads and heavy sleepers) have been thoroughly investigated in laboratory tests to establish the static and dynamic parameters as well as their serviceability. Finally, field tests at and near railway tracks with and without under sleeper pads have been performed. To determine the reduction effect of the isolated track, the ground vibrations excited by trains or artificial sources have been measured. The soil properties at the different sites have also been measured so that the comparison of the isolated and un-isolated track can take into account possible differences of the soil parameters. The contribution shows how the different (numerical, laboratory and field) methods and results can be combined to achieve an improved mitigation solution with soft under sleeper pads and heavy sleepers for ballasted and slab tracks. T2 - EURODYN 2014 - 9th International conference on structural dynamics CY - Porto, Portugal DA - 30.06.2014 KW - Railway track KW - Track-soil interaction KW - Mitigation KW - Under sleeper pads KW - Laboratory tests KW - Field tests KW - Ground vibration PY - 2014 SN - 978-972-752-165-4 SN - 2311-9020 SP - 805 EP - 812 AN - OPUS4-31164 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rücker, Werner A1 - Thöns, Sebastian A1 - Said, Samir A1 - Schmid, Wolfgang ED - Zingoni, A. T1 - SHM strategies, application and measurements on tripod offshore wind energy converters within the German offshore park Alpha Ventus N2 - Prototypes of wind turbines of the megawatt dass are to be built and tested until 2008 within a German offshore wind energy test field in the North Sea (ALPHA VENTUS). To ensure a high operational reliability of offshore wind turbines with economically acceptable repair and maintenance efforts, comprehensive diagnosis and supervision concepts are required. Automatic monitoring Systems will be an essential part of such concepts. Because of the fact, that during Operation there will be static and dynamic interaction between the components ‘structure’, ‘machinery’ and ‘blades’ it is necessary to develop the monitoring techniques in an overall concept. These monitoring Systems are supposed to be applied for the design and testing as well as for the Operation and maintenance phases. In the paper the developed approaches for the measurement of actions and the condition monitoring of all components of an offshore wind energy plant will be shown. T2 - Research and applications in structural engineering, mechanics and computation - 5th International conference on structural engineering, mechanics and computation CY - Cape Town, South Africa DA - 02.09.2013 PY - 2013 SN - 978-1-138-00061-2 SN - 978-1-315-85078-8 SP - 977 EP - 982 PB - CRC Press AN - OPUS4-29104 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Auersch, Lutz A1 - Said, Samir ED - Gao, G. T1 - The influence of soil properties on the ground vibration due to railway traffic and other sources - the comparability of different sites T2 - 6th International symposium on environmental vibration: Prediction, monitoring, mitigation and evaluation - Advances in environmental vibration CY - Shanghai, China DA - 2013-11-08 KW - Soil properties KW - Railway track KW - Ground vibration KW - Measurement KW - Assessment KW - Mitigation PY - 2013 SN - 978-7-5608-5303-1 SP - 175 EP - 186 PB - Tongji University Press AN - OPUS4-29731 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hu, Wei-Hua A1 - Rohrmann, Rolf A1 - Said, Samir A1 - Rücker, Werner ED - Xu, Y. L. ED - Zhu, S. ED - Xia, Y. ED - Ni, Y.Q. ED - Law, S.S. ED - Yin, J. H. ED - Su, Z.Q. T1 - Development of a vibration-based structural health monitoring system for wind turbines N2 - In the context of national innovative project IMO-WIND, an integrated long term monitoring System was installed on a prototype of an offshore wind turbine System of 5 megawatt dass. The Federal Institute for Materials Research and Testing (BAM) was responsible for development of the SHM System. It consists of a signal acquisition System and a Signal processing and management System. The signal acquisition System is composed of 14 acceleration sensors, 110 strain gauges and 4 inclination sensors, installed at the tripod foundation and the tower. It began to work in August 2007. In order to investigate the structural dynamic properties, extract efficient damage index and manage huge amounts of Vibration Signals and analysis results, an automated signal processing and management Software System is developed in LabVIEW® environment. It includes functions such as automated Operational Modal Analysis (OMA) on the basis of Stochastic Subspace Identification (SSI) method and poly-reference Least-Squares Complex Frequency Domain (p-LSCF) approach, investigation of environmental/operational effects on structural dynamic properties under operational conditions, features extraction using Principal Component Regression (PCR) and Multiple Linear Regression (MLR) as well as data/result management and visualization. Besides, this paper also presents variations of structural modal parameters of a wind turbine system under complex environmental/operational conditions. Comparison of modal parameters automatically extracted by SSI method and poly-reference p-LSCF approach indicates that the latter method provides more stable modal identification results ffom the viewpoint of long term OMA. Subsequently, the influences of temperature, wind velocity, rotation speed and nacelle direction on modal parameters are generally discussed. Finally, variations of indentified modal parameters during two years are presented. T2 - SHMII-6 - 6th International conference on structural health monitoring of intelligent infrastructure CY - Hong Kong, China DA - 09.12.2013 KW - Wind turbine KW - Vibration-based structural health monitoring system KW - Automated operational modal analysis KW - Environmental and operational effects KW - Feature extraction KW - Damage detection PY - 2013 SN - 978-962-367-768-4 SP - 1 EP - 10 AN - OPUS4-32973 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Grasse, Fabian A1 - Trappe, Volker A1 - Thöns, Sebastian A1 - Said, Samir ED - De Roeck, G. ED - Degrande, G. ED - Lombaert, G. ED - Müller, G. T1 - Structural health monitoring of wind turbine blades by strain measurement and vibration analysis N2 - Wind turbine blades have to withstand a high number of load cycles in mostly hard weather conditions over 20 years. In a research project BAM and several partners have designed, evaluated and tested a condition monitoring system for all parts of a wind turbine. At a rotorblade with a length of 58 m fibre bragg grating sensors were applied for in-service strain measurement. Additionally a complex test rig was designed to enable real biaxial loading conditions at a representative test rotor blade to simulate the mechanical loading conditions in the lab. In this test blade with a length of 8 m also fibre bragg grating sensors were implemented to determine their influences for the structure and the condition monitoring system. Vibration measurements were carried out at different test phases. The results were compared with finite element strain and modal analysis. T2 - EURODYN 2011 - 8th International conference on structural dynamics CY - Leuven, Belgium DA - 04.07.2011 KW - Rotor blade KW - Test blade KW - Modal analysis KW - Condition monitoring PY - 2011 SN - 978-90-760-1931-4 IS - MS25 Tue SP - 3490 EP - 3497 AN - OPUS4-25076 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Auersch, Lutz A1 - Said, Samir ED - Zhai, W. ED - Takemiya, H. ED - De Roeck, G. ED - Tutumluer, E. T1 - Experimental soil parameters by different evaluation methods for impulsive, train and ambient excitation T2 - ISEV 2011 - 5th International symposium on environmental vibration - Advances in environmental vibration CY - Chengdu, China DA - 2011-10-20 KW - Wave velocity KW - Dispersion KW - SASW KW - MASW KW - SPAC KW - Damping PY - 2011 SN - 978-7-03-032373-6 SP - 3 EP - 9 PB - Science Press AN - OPUS4-24807 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rohrmann, Rolf A1 - Thöns, Sebastian A1 - Rücker, Werner A1 - Bicker, S. A1 - Said, Samir A1 - Schmid, Wolfgang T1 - Structural investigations and monitoring results on a prototype of offshore wind turbines of multibrid M5000 series N2 - The concept and technical details of the implementation of the developed integrated monitoring system within the IMO-WIND project are presented. The tasks of the components of the system and its requirements are described. Selected results from the continuous monitoring during operation of the plant M5000_2 regarding the task design verification and dynamic structural analysis are given. T2 - DEWEK 2010 - 10th German wind energy conference CY - Bremen, Germany DA - 2010-11-17 KW - Integrated monitoring system KW - Offshore wind turbines KW - Design verification KW - Structural assessment KW - Limit values KW - Load transfer KW - Data management KW - Dynamic analysis KW - Rotor blades KW - Embedded sensors PY - 2011 IS - S03 SP - 1 EP - 5 PB - DEWI GmbH AN - OPUS4-23712 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rohrmann, Rolf A1 - Said, Samir A1 - Schmid, Wolfgang A1 - Thöns, Sebastian A1 - Bicker, S. A1 - Rücker, Werner ED - De Roeck, G. ED - Degrande, G. ED - Lombaert, G. ED - Müller, G. T1 - Results from monitoring and assessment of offshore wind turbines N2 - To ensure a high operational reliability of offshore wind turbines (OWEC) with economically acceptable repair and maintenance efforts, comprehensive diagnosis and supervision concepts are required. Automatic monitoring Systems will be an essential part of such concepts. Because of the fact, that during Operation there will be static and dynamic interaction between the components ‘structure’, ‘machinery’ and ‘blades’ it is necessary to develop the monitoring techniques in an overall concept. These monitoring Systems are supposed to be applied for the design and testing as well as for the Operation and maintenance phases. The knowledge of the dynamic behavior of wind turbines is important both for the design and for a safe Operation. The available monitoring data from a period of three years, allow first conclusions on the long-term Operation of such Systems in terms of quality requirements to the instrumentation to the structure and the rotor blades T2 - EURODYN 2011 - 8th International conference on structural dynamics CY - Leuven, Belgium DA - 04.07.2011 KW - Integrated monitoring system KW - Offshore wind turbines KW - Structural assessment KW - Limit values KW - Measurement hardware KW - Data management KW - Embedded FBG sensors KW - Data analysis KW - Damage detection KW - Rotor blades PY - 2011 SN - 978-90-760-1931-4 IS - MS25 SP - 3450 EP - 3456 AN - OPUS4-24293 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Auersch, Lutz A1 - Said, Samir T1 - Attenuation of ground vibrations due to different technical sources N2 - The attenuation of technically induced surface waves is studied theoretically and experimentally. In this paper, nineteen measurements of ground vibrations induced by eight different technical sources including road and rail traffic, vibratory and impulsive construction work or pile driving, explosions, hammer impulses and mass drops are described, and it is shown that the technically induced ground vibrations exhibit a power-law attenuation ν ~ r -q where the exponents q are in the range of 0.5 to 2.0 and depend on the source types. Comparisons performed demonstrate that the measured exponents are considerably higher than theoretically expected. Some potential effects on ground vibration attenuation are theoretically analyzed. The most important effect is due to the material or scattering damping. Each frequency component is attenuated exponentially as exp(-kr), but for a broad-band excitation, the sum of the exponential laws also yields a power law but with a high exponent. Additional effects are discussed, for example the dispersion of the Rayleigh wave due to soil layering, which yields an additional exponent of 0.5 in cases of impulsive loading. KW - Wave attenuation KW - Environmental vibrations KW - Field tests KW - Material damping KW - Scattering damping KW - Rayleigh wave PY - 2010 DO - https://doi.org/10.1007/s11803-010-0018-0 SN - 1671-3664 VL - 9 IS - 3 SP - 337 EP - 344 PB - Science Press CY - Beijing, China AN - OPUS4-22124 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Auersch, Lutz A1 - Said, Samir ED - Xia, H. ED - Takemiya, H. T1 - Environmental vibrations due to different technical sources, amplitude-distance laws in experiment and theory T2 - 4th International Symposium on Environmental Vibration: Prediction, Monitoring and Evaluation (ISEV2009) CY - Beijing, China DA - 2009-10-28 KW - Amplitude-distance laws KW - Environmental vibrations KW - Field tests KW - Wave theory of attenuation PY - 2009 SN - 978-7-03-025765-9 VL - I SP - 757 EP - 762 PB - Science Press CY - Beijing, China AN - OPUS4-20788 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Auersch, Lutz A1 - Said, Samir A1 - Schmid, Wolfgang A1 - Wuttke, Wilfried T1 - Experimental and theoretical building and foundation behaviour T2 - EVACES'09 - Experimental vibration analysis for civil engineering structures CY - Wroclav, Poland DA - 2009-10-14 PY - 2009 SN - 978-83-7125-184-9 N1 - Serientitel: AIP conference proceedings – Series title: AIP conference proceedings SP - 133 EP - 142 AN - OPUS4-31259 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rohrmann, Rolf A1 - Rücker, Werner A1 - Thöns, Sebastian A1 - Said, Samir T1 - Design and operation of integrated monitoring systems for offshore wind turbines N2 - To ensure a high operational reliability of future generations of offshore wind conversion systems (OWEC) with economically acceptable repair and maintenance efforts, comprehensive diagnosis and supervision concepts are required. Automatic monitoring systems will be an essential part of such concepts. Because of the fact, that during operation there will be static and dynamic interaction between the components 'structure', 'machinery' and 'blades' it is necessary to develop the monitoring techniques in an overall concept. These monitoring systems are supposed to be applied for the design and testing as well as for the operation and maintenance phases. The used methods are focused on the design requirements for the structure, which are stated in the respective standards and certification guidelines. For the validation of the design, methods are specified which would be also applicable for SHM in the operating condition, e.g. for the evaluation of the structural conditon possibly after the occurrence of damages or changes. The further task consists in the realization of condition monitoring for all components, aiming at early damage detection and the observation of the damage development and its evaluation. Here the task consists of determining with assessment procedures the optimum time for maintenance actions to be carried out. T2 - DEWEK 2008 - 9th German wind energy conference CY - Bremen, Germany DA - 2008-11-26 KW - Integrated monitoring system KW - Offshore wind turbines KW - Assessment KW - Damage identification KW - Load monitoring PY - 2008 SP - 1 EP - 4(?) AN - OPUS4-19872 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Said, Samir A1 - Auersch, Lutz T1 - Environmental vibration due to normal and extreme excitation: railway traffic, explosions and heavy mass drop tests T2 - ISEV 2007, 3rd International Symposium on Environmental Vibrations: Prediction, Monitoring, Mitigation and Evaluation CY - Taipei, Taiwan DA - 2007-11-28 PY - 2007 SP - 1 EP - 6 AN - OPUS4-18408 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Auersch, Lutz A1 - Said, Samir T1 - Simple modal analysis and wave propagation for practical floor experiments in new and old office and residential buildings T2 - EVACES'07 - Experimental vibration analysis for civil engineering structures CY - Porto, Portugal DA - 2007-10-24 PY - 2007 SN - 978-972-752-095-4 SP - 423 EP - 432 AN - OPUS4-18409 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Said, Samir A1 - Auersch, Lutz T1 - Environmental vibration due to railway traffic with different train speeds N2 - Measurement of railway vibration on a bridge, a surface and a tunnel line. Amplitude-distance law for different train speeds. Theoretical and experimental transfer functions of the soil. Spectra of the ground vibration at r = 3, 5, 10, 20, 30 and 50 m for the train speeds 60, 100, 160 km/h. T2 - 3rd International Symposium on Environmental Vibrations CY - Taipei, Taiwan DA - 28.11.2007 KW - Ground vibration KW - Train passage KW - Train speed PY - 2007 AN - OPUS4-47087 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Said, Samir A1 - Auersch, Lutz T1 - Environmental vibration due to explosions – propagation of different waves N2 - Time records of the soil response to the hammer and the Explosion excitation. Spectra of the soil response to the hammer and explosion excitation. Amplitude-distance law for different TNT weight equivalents. T2 - 3rd International Symposium on Environmental Vibrations CY - Taipei, Taiwan DA - 28.11.2007 KW - Explosion KW - Ground vibration KW - Wave propagation KW - Amplitude-distance law PY - 2007 AN - OPUS4-47088 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Said, Samir A1 - Auersch, Lutz T1 - Environmental vibration due to heavy mass drop N2 - Drop test facility of BAM and the location of strain, stress, velocity and acceleration sensors. Time records of the concrete strain, the soil stress and the foundation acceleration. T2 - 3rd International Symposium on Environmental Vibrations CY - Taipei, Taiwan DA - 28.11.2007 KW - Drop test KW - Foundation behaviour KW - Soil stress KW - Foundation strain KW - Foundation acceleration PY - 2007 AN - OPUS4-47089 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rücker, Werner A1 - Rohrmann, Rolf A1 - Said, Samir T1 - Offshore wind energy plants- a challenge for integrated structural health monitoring systems T2 - International Workshop on Lifetime Engineering of Civil Infrastructure CY - Ube Yamaguchi, Japan DA - 2005-11-09 KW - Offshore wind energy turbines KW - Structural health monitoring KW - Early damage detection KW - Control of dynamic behavior KW - Structural assessment PY - 2005 SP - 219 EP - 229 PB - Yamaguchi University CY - Ube Yamaguchi AN - OPUS4-12257 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rücker, Werner A1 - Rohrmann, Rolf A1 - Said, Samir T1 - Monitoring and assessment of structures under changed loading conditions T2 - SAMCO Summer Academy 2005 on Structural Assessment, Monitoring and control CY - Zell am See, Austria DA - 2005-09-05 KW - Monitoring KW - Assessment KW - Vibration PY - 2005 SP - 10 pages PB - Samco Network CY - Zell am See AN - OPUS4-11869 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Rohrmann, Rolf A1 - Said, Samir A1 - Schmid, Wolfgang ED - Watanabe, E. ED - Frangopol, D. T1 - Health monitoring of a steel bridge under heavy load traffic T2 - IABMAS '04 ; 2nd International Conference on Bridge Maintenance, Safety and Management CY - Kyoto, Japan DA - 2004-10-18 KW - Bridge Assessment KW - Heavy Load Traffic KW - Damage Detection KW - Structural Health Monitoring KW - Modal Analysis PY - 2004 SN - 90-5809-680-7 PB - Balkema CY - Leiden AN - OPUS4-4841 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Auersch, Lutz A1 - Semrau, Norbert A1 - Schmid, Wolfgang A1 - Said, Samir A1 - Rücker, Werner ED - Grundmann, H. ED - Schuëller, G. I. T1 - Theory and experiments on wave propagation, on track-soil and on soil-building interaction related to railway induced vibration T2 - 5th International Conference on Structural Dynamics ; 4th International Conference on Structural Dynamics ; EURODYN 2002 CY - Munich, Germany DA - 2002-09-02 PY - 2002 SN - 90-5809-512-6 VL - 2 SP - 1137 EP - 1142 PB - Balkema CY - Lisse AN - OPUS4-1595 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Auersch, Lutz A1 - Said, Samir A1 - Rücker, Werner ED - Sarsby, R. T1 - Prospecting soft deposits by wave propagation analysis in theory and experiment T2 - 3rd International Symposium on Geotechnics Related to the European Environment ; 3rd GREEN CY - Berlin, Germany DA - 2000-06-21 PY - 2001 SN - 0-7277-3004-5 SP - 65 EP - 73 PB - Telford CY - London AN - OPUS4-1594 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -